Fritz Pregl and Inquiry Based Learning

Fritz Pregl received the Nobel Prize for chemistry in the year 1923 because he had improved earlier methods of quantitative organic microanalysis, thus making possible the study of substances which are available only in small quantities (3-5 mg). The same quantity of substance, which had formerly been sufficient for only one analysis, from that time on could be used for more than 500 analyses. Pregl devoted himself to research into nitrogen and sulphur compounds, organic compounds containing chlorine, bromine and iodine and a number of other organic compounds. The importance of his work lay mainly in the fact that he made possible the study of mass, elementary composition, structure and the relations between elements in substances of which only a few mg were available. Thanks to his improvements, other scientists were able to work with greater precision. Biochemists were able to study the structure and function of enzymes, hormones, vitamins and other organic compounds which exist in the human body only in tiny quantities. Pregl’s working method still remains in use, although his name is not preserved. Fritz Pregl was born in 1896 in Ljubljana. His mother was Austrian and father Slovene who was a treasurer at the Kranjska hranilnica. When he was 6 his father died and he remained alone with his mother. After elementary school he attended the classical grammar school in Ljubljana. Throughout his grammar school years he distinguished himself primarily in science subjects with the exception of mathematics. He had poor results also in humanities and social sciences and in Slovene language. After grammar school he moved to Graz to the nearest university to study medicine. Despite his relatively average school results he became a brilliant student. After graduating in medicine (1899) he completed his doctoral thesis entitled The Causes of high value of the coefficient in normal human urine. Although he was being offered several distinguished positions at different universities in Austria, he requested study leave for post doctoral education. He visited the most important laboratories in Europe. During that period he worked and studied with Wilhelm Ostwald and Emil Fischer. When he returned to Graz he was engaged at the Institute of Medicinal Biochemistry as chief forensic expert. After 1913 he became director and professor at the same institute. Pregl and his colleagues succeeded in reducing the quantity of test substance and shortening the working time. At that time Pregl required approximately 10 mg of substance for analysis. Ten to a hundred times less than usual. For example, to study male sexual hormones in order to obtain 15 mg of pure hormones, had previously required no less than 15 000 litres of urine (Pregl, 2006). The foundations of elementary organic analysis were laid by Liebig and Dumas. For determination of carbon and hydrogen, the substance was combusted and the escaped gases were